Is it possible...?

... to change the sound effects that play whenever you exit?

Wrong forum

Oopsy...
Maybe this belonged in the Editing Forum.

Yeppers :)
To answer your question, the sound effects that are played at the tally screen at the end of a level are the explosion sound effects. Therefore all you would have to do is replace the explosion sound effect with a sound effect of your choice.

By exit, I mean "leave the game."
You know how it always plays a random sound effect when you leave the game (with most ports).

I think it just plays some random sound, so you'd probably have to edit the source to change it.

Of all aspects of Doom, I think those random sounds would have to be the most pointless thing in the whole game. I mean, they could have at least chose some good ones to play...